In known hydraulic pressure transformers, the ports in the rotating unit are normally circular in cross-section and the ends of the respective ports in the port plate are normally semi-circular in cross-section. Consequently, as the respective ones of the ports in the rotating unit initiates communication with the respective ones of the slots in the port plate, the opening is small and increase in size to its maximum amount. Since this communication is happening at locations other than top or bottom dead center positions, the instantaneous velocity of the pistons within the rotating unit is high. Likewise, the volume of fluid being received or expelled is high. Since the initial opening is small, the high volume of fluid does not have a free, unrestricted path and the system efficiency is adversely affected. Additionally, in known pressure transformers, the circumferential space between the adjacent arcuate slots is longer than the circumferential length of the respective cylinder ports in the rotating unit. Consequently, at the times that the piston velocity is high and the flow being introduced or expelled from the piston cylinder is also high, the cylinder is totally blocked thus resulting in the trapped fluid being compressed prior to the cylinder opening to one of the arcuate slots.
The present invention is directed to overcoming one or more of the problems as set forth above.